Large modular joints in cable-supported bridges

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The proper installation of sensibly selected, well-designed expansion joints in bridges is a key factor in ensuring durability and minimising life-cycle costs. This is especially true for the large expansion joints generally required by cable-supported bridges, which can present very significant challenges – for example, due to their size, which can make transport from factory to site and installation very difficult, or due to the connections to steel superstructures that more often arise in long-span bridges. By describing such challenges, our paper on this subject, recently presented at the 2018 International Cable Supported Bridge Operators’ Conference (ICSBOC), can enable designers and constructors of major bridges to gain a valuable deeper understanding of the subject. 

The following images illustrate some of these challenges and solutions, and the paper can be downloaded here for further information – but please contact us if we can assist you in relation to this or any other matter.

Transportation challenges associated with very large expansion joints

New Tappan Zee Bridge, New York (2017): Road transport to site of 18-gap TENSA®MODULAR joints (each 29 m [95 ft] long and weighing 57,000 kg [125,000 lbs]) required special permits and a police escort

Incheon Grand Bridge, South Korea (2009): Two 24-gap TENSA®MODULAR joints being secured in a ship’s hull for transport to site

Run Yang – Nan Cha Bridge, China (2005): Due to their size, each with a length of 16.25 m [53 ft] and weighing more than 55,000 kg [120,000 lbs], these 27-gap TENSA®MODULAR joints were delivered in parts and re-assembled on the bridge deck

Challenges associated with lifting into position on site

Audubon Bridge, Louisiana (2010): Installation of extraordinarily large TENSA®FINGER sliding finger joints with a movement capacity of 1240 mm (49 inches) – following on-site connection of drainage channels to joints

Incheon Grand Bridge, South Korea (2009): Lifting of a 24-gap TENSA®MODULAR joints into position in the bridge deck

New Tappan Zee Bridge, New York (2017): Lifting of an 18-gap TENSA®MODULAR joint onto the bridge deck from a barge on the river 49 m [160 ft] below, using a floating crane

Connection to the main structure – design and execution considerations

Chongming Bridge, China (2008): Connection to the deck of this 22-gap TENSA®MODULAR joint by concreting (after spot welding to secure in position) was relatively straightforward

Lillebaelt Bridge, Denmark (2002): Cable-supported bridges with steel superstructures often require “steel connections” as opposed to concreted ones, considerably increasing design, fabrication and installation effort – as was the case for this bridge’s 14-gap TENSA®MODULAR joints

Angus L. Macdonald Bridge, Halifax, Canada (2017): Installation of a 7-gap TENSA®MODULAR joint – again with the added complexity and challenges of the required steel connections

Further installation considerations

Queensferry Crossing, Scotland (2017): Adjustment of pre-setting during installation of a 23-gap TENSA®MODULAR joint. Adjustment of pre-setting of very large joints can be especially demanding, especially on long steel cable-supported structures, since the pre-setting requirement (the width of the bridge’s movement gap) may change significantly on the day of installation

Audubon Bridge, Louisiana (2010): Manual adjustment of pre-setting of very large TENSA®FINGER sliding finger joints. Alternatively, long cable-supported bridges may experience enough natural movement in their daily expansion/contraction cycle to enable this to be used to adjust pre-setting

Incheon Grand Bridge, South Korea (2009): When fully installed (ideally with surface 2 to 5 mm [0.08 to 0.2 in] below the road surface), an expansion joint should provide a safe driving surface. In the case of this very large TENSA®MODULAR joint, anti-skid surfacing has been applied to half of the driving surface to improve tire grip

Designing for the future with easily replaceable expansion joints

The Quick-Exchange (or Quick-Ex) approach to design of the TENSA®MODULAR joint enables the mechanical part of the joint to be easily replaced at the end of the joint’s service life, with no impact on the bridge structure and minimal impact on traffic

The “Quick-Ex” design enables a TENSA®MODULAR joint’s main mechanical structure, consisting primarily of its surface centerbeams and the support bars beneath, to be easily replaced following unscrewing and removal of specially provided surface plates

NEWS-Paper-on-installation-of-joints-Köhlbrand Bridge-img2

Köhlbrand Bridge, Hamburg, Germany (2017): View of a TENSA®MODULAR joint (with noise-reducing “sinus plates” on the surface) as installed. The steel plates along both sides of the joint can be simply unscrewed to enable the joint to be easily removed and replaced when needed